[SoC] GDAL DWG Support [Week 6]

[Pero Brbora]

> As far as I can see Latest commits to libopencad crashed CAD Driver  
> on my Mac. GDAL still builts fine, but calling ogrinfo with DWG file  
> causes an endless loop somewhere in libopencad, however, tests are  
> passed and cadinfo app works just fine. Currently I have no idea  
> what can cause such behavior, and I am working on it.
I tried your code and it enters endless loop here too. You should  
enable debuging by default at this stage of development. I will try  
debuging with gdb.

As for CRC calculations. You should save object start position (after  
the size in bytes field). Add size in bytes offset to it and there it  
is CRC data.

Bye